The present invention relates to a waterproof structure that is applied to a vehicle lighting device having a shell formed by a case and a lens and that prevents water from entering an accommodation portion surrounded by the case and the lens.
Vehicle lighting devices mounted on the exterior of a vehicle for use have been proposed that have a shell formed by a case and a lens and include a light emitter arranged in an accommodation portion surrounded by the case and the lens. The vehicle lighting devices include a waterproof member arranged between the case and the lens and on the outer side of the accommodation portion to prevent water from entering the accommodation portion. The case and the lens are joined by joining portions.
The joining portions are formed by combinations of, for example, hooks located on one of the case and the lens and outward of the waterproof member and catches located on the other one of the case and the lens and outward of the waterproof member. When the case and the lens are joined together, either the hooks or the catches are elastically deformed outward so that the hooks enter the catches from the side closer to the accommodation portion, and an engaging surface of each hook is engaged with a catch surface of the associated catch.
The waterproof structures in which the case and the lens that sandwich the waterproof member are joined by engaging the hooks with the catches as described above have been disclosed in, for example, Japanese Patent No. 3286162 and Japanese Laid-Open Utility Model Publication No. 7-30412.
When an elastic waterproof member is used and the waterproof member is compressed by the joining operation, a reactive force acts on the case and the lens. Thus, depending on the shape or the engaging state of the hooks and the catches, either the hooks or the catches are elastically deformed outward and act to slide along the engaging surfaces and the catch surfaces in a disengaging direction. If an external force is applied to the vehicle lighting device during usage or if thermal expansion or warpage occurs under such a circumstance, the hooks may possibly escape from the catches.